Method and apparatus for adding treating agents to molten metal

ABSTRACT

A method and apparatus for adding treating agents to molten metal in which the agent, in wire-form is fed through a passage provided in an internally cooled stopper rod, thereby introducing the treating agent directly into the nozzle and to a stream of molten metal as it is discharged therethrough. The method is particularly applicable for adding treating agents to steel for completely deoxidizing same with agents such as aluminum, titanium or zirconium. The stopper rod is adapted to seat into the entrance of the nozzle as a valve seat, with the stopper rod constructed in hollow form with a centrally disposed passage extending axially therethrough for feeding the wire completely through the stopper to the bottom of the ladle. The treating agent is protected from excessive heat by cooling it by means of a special stopper rod construction, in which means are provided for circulating cool air in surrounding relation to the treating agent within the stopper rod, and the rod itself is constructed of an insulating outer wall.

United States Patent Caudill et al.

[ METHOD AND APPARATUS FOR ADDING TREATING AGENTS TO MOLTEN lVlETAL [75]Inventors: Maurice L. Caudill, Peoria, 111.;

Steven C. Cochran, Louisville, Ky.; Donald C. Loebach, East Peoria, Ill.

[73] Assignee: Caterpillar Tractor Company,

Peoria, Ill.

[22] Filed: July 12, 1974 [21] App]. No.: 487,934

United Kingdom 164/57 Primary ExaminerFrancis S. Husar AssistantExaminer-John E. Roethel Attorney, Agent, or Firm-Phillips, Moore,Weissenberger Lempio & Strabala Oct. 14, 1975 [57] ABSTRACT A method andapparatus for adding treating agents to molten metal in which the agent,in wire-form is fed through a passage provided in an internally cooledstopper rod, thereby introducing the treating agent directly into thenozzle and to a stream of molten metal as it is discharged therethrough.The method is particularly applicable for adding treating agents tosteel for completely deoxidizing same with agents such as aluminum,titanium or zirconium. The stopper rod is adapted to seat into theentrance of the nozzle as a valve seat, with the stopper rod constructedin hollow form with a centrally disposed passage extending axiallytherethrough for feeding the wire completely through the stopper to thebottom of the ladle. The treating agent is protected from excessive heatby cooling it by means of a special stopper rod construction, in whichmeans are provided for circulating cool air in surrounding relation 'tothe treating agent within the stopper rod, and the rod itself isconstructed of an insulating outer wall.

12 Claims, 3 briwing Figures I\ i9 67\ r U.S. Patent Oct. 14, 1975 7 1METHOD AND APPARATUS FOR ADDING TREATING AGENTS TO MOLTEN METALBACKGROUND OF THE INVENTION The present invention relates to amethod andapparatus for adding treating agents to molten metal, and moreparticularly to a method and apparatus for adding deoxidants to steeljust prior to the casting thereof.

lt is well known that certain treating agents should be added to themolten metal to be cast soon prior to the casting thereof in order toprevent the advantageous characteristics of the additive from undulyfading prior to the set-up of the casting in the mold. This isparticularly true when it is desired to make fully killed steel castingsby the additions of deoxidants thereto. For instance, even thoughsufficient deoxiding agents may be added to fully deoxidize the steel inthe ladle, unless the melt is protected from an inert atmospherereoxidation will occur during the subsequent stirring, holding andpouring operations of the molten metal. It is therefore advantageous toadd treating agents which have a time limited effectiveness as late inthe pouring process as possible.

Heretofore it has frequently been necessary to add excess amounts oftreating agents to compensate for the above described limitations. Notonly has this practice been costly, but it should be remembered that theaddition of any agent will influence the alloy content of the finishedcasting. Since melt chemistry must be closely controlled to assure thatthe desired physical properties are present in the finished casting,treating agents cannot be added indiscriminately. It is thereforedesirable to make the most efficacious use of any materials which areadded.

Aluminum is economically favored as a deoxidizing or killing agent forsteel, but it cannot be used in sufficient amounts to fully kill steelwhen added by any of the present methods heretofore in use. For example,one of the methods now in use is to add the treating agent to the ladleso that sufficient mixing will occur and the steel will be killedthroughout the entire composition. However, deoxidants such as aluminum,after combining with oxygen, tend to precipitate out of the moltensolution and build up at the ladle or tundish nozzle and cause excessiveclogging thereof.

Accordingly, it has been a common practice to employ an oversized nozzleand stopper rod so that as precipitate buildup at the nozzle increases,the stopper rod must be increasingly raised to partially compensate forthe reduced nozzle flow area. However, such practice is only minimallyeffective, as the buildup will continue until the nozzle is completedplugged. This makes it necessary to replace the nozzle frequently.Additionally, the buildup of material at the nozzle makes it difficultto closely regulate the metal flow rate so that such processes are noteasily adaptable for automation.

Similar problems have been encountered when using silicone, manganese,titanium, zirconium and similar materials which combine with oxygen toform high melting point compositions. The melting point of suchcompositions, which are loosely classified as ceramic or refractorycompounds, is substantially higher than the normal molten steel solutiontemperature. Also, the temperature of the pouring nozzle, particularlyearly in the pour, may be substantially lower than the molten metaltemperature in the ladle. This encourages more rapid precipitation ofhigher melting point compositions out of solution at the nozzlesurfaces.

SUMMARY OF THE INVENTION From the foregoing discussion, it is seen thatthe primary object of the invention is to provide a method and apparatusfor adding treating agents into a molten metal about to be cast, inwhich the treated molten metal is protected from recontamination fromatmospheric contact, and in which substantially complete mixing andtreatment of the molten metal occurs prior to the metal setting up incast form.

Another object of the invention is to provide a method and apparatus foradding deoxidizing agents to steel in which the deoxidizing agent isadded to a closed stream of metal moving from a ladle or like reservoirto the casting mold.

A further object of the invention is to provide a method and apparatusof the character described in which high melting oxides produced bycertain treating agents do not build up in restricted areas and impedenormal continued operation of the process and apparatus.

Yet still another object of the invention is to provide a method andapparatus of the character described in which the process may becarefully controlled, is suitable for automation, and in which maximumuse of the treating agents is obtained.

Further objects and advantages of the invention will become moreapparent as the specification progresses.

In accordance with the apparatus form of the invention, an apparatus isprovided for adding treating agents to molten metal as it flows from asupply reservoir or ladle into a mold. The apparatus comprises a nozzleformed in the bottom of said reservoir or ladle adapted to delivermolten metal to a mold, a valve seat formed at the inlet end of saidnozzle, a stopper rod formed to move into and out of fitting relationwith said valve seat for controlling the flow of metal through saidnozzle, said stopper rod being formed with a hollow interior insurrounding relation to a central passage, means for supplying awire-like treating agent through said central passage, and means forcirculating cooling fluid through said hollow interior.

Thus, it is seen that the, apparatus provides a ladle having a nozzleand a stopper rod adapted to allow molten metal to flow through saidnozzle in a controlled stream. The nozzle and valve seat are constructedso that the maximum velocity of the molten metal flow will occur throughthe valving and nozzle and no reverse flow of molten metal occurs. Thewire-like treating agent is moved down into the nozzle past the valvedportion of flow of the molten metal so as to prevent the formation ofoxides at the valve seat that would interfere with the operationthereof. In addition, the treating agent is added at the central portionof the nozzle where velocity flow is at a high rate so that it isquickly carried on through the nozzle in the narrow stream whereintimate mixing occurs and provides a melt adapted to be immediatelymolded. I

The wire-like feeding means is provided with a direct drive motor sothat the quantity of treating agent may be accurately metered and theapparatus is designed to use wire-like treating agents now available onthe market. In addition, the stopper rod is adapted for controlledopening and closing so that the pouring of metal through the nozzle andthe addition of treating agent may be accurately coordinated. Sincethese operations are mechanized, it is seen that the apparatus is welladapted for automation, if desired.

In accordance with the method form of the invention, a method isprovided for adding treating agents to a molten metal stream as it isprovided from a nozzle in a ladle or the like and delivered directlyinto a mold. Specifically, the method comprises the steps of adding saidtreating agent to the molten stream substantially within the nozzle inan amount SUfflClCI'lt to treat the metal being cast. Preferably, thewire-like treating agent is added to the central portion of the streamand is retained at near outside ambient temperature prior to entranceinto the molten stream. In addition, the method provides for a residencetime of treating agent in the nozzle to be very low with a high velocitystream of metal being provided through the nozzle so that the treatingagent is immediately carried therethrough as it is added. Thus,deposition of oxides at the forward end of the nozzle and within thenozzle itself is positively prevented.

BRIEF DESCRIPTION OF THE DRAWING A preferred form of the invention isillustrated in the accompanying drawings forming a part of thisdescription, in which:

FIG. 1 is an elevational view of an apparatus constructed according tothe invention together with a fragmentary cross-sectional portion of aladle in which it is installed;

FIG. 2 is an enlarged fragmentary view partly in section illustratingthe area marked by circle 2 of FIG. 1; and

FIG. 3 is an enlarged fragmentary, cross-sectional view of the apparatustaken in the area indicated by circle 3 of FIG. 1. t While only thepreferred form of the invention is shown, it should be understood thatvarious changes or modifications may be made within the scope of theclaims attached hereto without departing from the spirit of theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring moreparticularly to the drawings, there is shown in FIG. 1, an apparatus 11for adding treating agents 12 in wire-like form to molten metal as itflows from a supply reservior or ladle 13 into a mold (not shown) formedfor easing metals. The ladle includes a side refractory lining l4 and abottom refractory lining 16 disposed within a suitable-housing 17. Anozzle 18 is fit into the bottom of the ladle in a manner makingreplacement of the nozzle relatively easy. Thus, the nozzle 18 isconstructed of a suitable ceramic or refractory material 19 and has avertically extending cylindri-' cal bore 21 communicating at its upperend with a conical valve seat 22. The nozzle is fit into a suitable borein the bottom of ladle 13 for providing avalve seat and nozzle passageat and through the bottom. The nozzle is secured as shown by a plate 23attached to housing 17.

A stopper rod assembly 24 is mounted on the ladle housing and comprisesa stopper rod 26 having a curved lower end 27 formed to move into andout of fitting relation with the valve seat 22, and means 28 for axiallymoving the stopper rod 26. Stopper rod 26 is formed with a cylindricalceramic wall 29 fitting against end 27, which is also composed ofceramic material. These parts define a hollow interior 31 in which isfit a tubular member 32. The tubular member 32 has a hollow central areathrough which the wire-like treating agent 12 is moved.

Referring more particularly to FIGS. 2 and 3, it is seen that thetubular member 32 is composed of metal and has threads 33 at its upperend, with the member being threaded through a gooseneck 34 and securedin threaded position by nuts 36 and 37. The hollow interior 31 betweenthe tubular member 32 and the ceramic wall 29 is further divided into aninner annular chamber 38 and an outer annular chamber-39 by a tubularbaffle 41 which has its upper end welded to or otherwise secured to aplate 42. The plate 42 has an inlet tube 43 for communicating compressedair or like cooling fluid to the internal chamber 38 and an outlet 44 toprovide for egress of such fluid from the outer annular chamber 39.

The stopper rod assembly is assembled and held together as follows.First, the ceramic wall 29 is provided with a threaded ceramic bushing46 (see FIG. 3), which is fit in place, and then tubular member 32 isfit within the hollow interior. The member 32 has a flanged lower end47, which is fit in abutting relation against bushing 46. The plate 42and its associated baffle 41 is then fit over the tubular member, and anut 48 is threaded over threaded portion 33 of tubular member 32 againstthe upper portion of plate 42, so as to clampingly cooperate with flange47 of the tubular member and hold the assembly together. The lower end27 of the stopper rod is then threaded over bushing 46, nut. 37 screwedinto position, and the tubular member threaded through gooseneck 34.Then nut 36 is screwed on and nuts 36 and 37 tightened in place with thegooseneck positioned as desired. The wire feeding means 12 is thenthreaded down through the interior 49 of tubular member 32, and theinterior 51 of end 27.

In order to feed the wire-like treating agents 12, feeding means 52 isprovided for supplying the treating agent through the central interiorpassages 51 and 49 and down into a central location within bore 21 ofnozzle 18. Feeding means 52 comprises a plurality of drive rollers 53mounted for rotation on a bracket 54, which in turn is secured to thegooseneck 34. The drive rollers are driven by a suitable electric motor(not shown) mounted at the rear of the bracket, and formed withappropriate drive means or control means whereby the driving velocity ofdrive rollers 53 may be accurately adjusted.

The means 28 for moving the stopper rod 26 up and down in an axialdirection comprises a barrel housing 56 attached to the ladle housing 17by a support bracket 57, and a slide 58 slidably positioned within thebarrel housing. The slide is vertically adjusted with respect to thebarrel housing by means of an adjustment crank 59 which is rotatablymounted on the ladle housing. The adjustment crank has a plurality ofpinion teeth 61 which engage threads provided on a rack portion (notshown) of the slide to raise or lower the slide. The slide is rotatablypositioned by means of a control lever 62 pivotally attached to thelower end of the slide. The slide may be locked in fixed axial androtational position by clamp assembly 63 mounted on the barrel housingand actuated by a lever arm 64. The slide 58 is connected at its upperend to the gooseneck 34 which in turn is connected to the stopper rod 26as described above.

In operation, the ladle is filled and the nozzle positioned to delivermolten metal to a mold. In addition, the wire-like treating agent 12 ispositioned so that it extends just down through the end of the stopperrod. The stopper rod is then lifted by operation of crank 59, and thewire-like treating agent is simultaneously threaded down through thestopper rod by operation of the feeding means 52. By accurately matchingthe flow I rate, which can be determined by calibration, with the rateof feed of the wire treating agent 12, an accurate addition of treatingagent may be provided into the nozzle where the moving molten streamimmediately melts and mixes the treating agent throughout.

Thus, in its method aspect, the invention provides a method of addingtreating agents to a molten metal stream provided from a nozzle in aladle or the like and delivered directly into a mold comprising thesteps of adding said treating agent to the molten stream substantiallywithin the nozzle in an amount sufficient to treat the metal being cast.In addition, provision is made for adding the wire-like treating agentto the central portion of the stream. Moreover, cooling means areprovided to retain the wire feeding means at a relatively lowtemperature prior to entrance of the treating material into the metalstream. This temperature control is made possible by the addition ofcompressed air or like cooling fluid through tube 43 which maintains arelatively cool atmosphere surrounding the tubular member 32 which ismetal and tends to transfer its heat easily to the air. The partiallyheated air then travels around the baffle and continues to cool bycooling the inner surface of the ceramic wall 29. The ceramic wall 29serves as an insulator between the interior of the stopper rod and themolten metal. carried on the outside thereof, and this constructionallows excellent protection for the treating agent. It is also notedthat the residence time of the metal added to the nozzle is very lowbecause of the comparatively high velocity of the molten stream passingthrough the nozzle and therefore deposition of oxides at the valve seatis positively prevented and deposition within the nozzle issubstantially prevented.

It should be noted that as the stream of molten metal exits from thenozzle, it has a vortex or swirl flow characteristic, in addition to thevertical flow velocity, which serves to mix the treating agent into themolten solution for effective treatment throughout all of the moltenmetal. Further mixing, although not necessarily required, also occurswithin the sprue, gating system, and casting cavity of the mold.

The present invention also permits unusual flexibility in controllingthe amount and rate of additions to the molten metal. The wire feed ratemay be automatically determined for a given nozzle opening or pour rate,or the rate may be manually controlled by the ladle operator. The wirecomposition may be selected to provide a single treatment, such asdeoxidation, or a plurality of treatments such as inoculation, grainrefinement and alloy addition in addition to or in lieu of deoxidation.

By way of example, the wire-like treating agent 12, as shown in FIG. 3,has an aluminum core 66 circumscribed by a steel sheath 67 to providerigidity at high temperatures and protection against premature meltingof the aluminum core. With such construction, it will be appreciatedthat other treating agents may be carried, in adidtion to, or insteadof, aluminum in the core area. With the stopper nozzle constructedaccording to the invention, and cooling provided, it is thus seen thatcomparatively volatile agents may be added to the molten metal, ifdesired, since protection is provided'for such agents until they reachthe point of use.

The amount of deoxidant required will generally exceed the amount theymay be conveniently added through the wire feeders. In such cases, it ispreferred to partially kill the steel in the process somewhere inadvance of the nozzle, and then fully kill the steel at the nozzle inaccordance with the invention.

In a typical run, the base metal is melted and refined in an arc orinduction melting furnace. The metal is brought up to tap temperatureand tapped into the receiving ladle while final alloy adjustments areshoveled into tap stream. At this time, vacuum degassing is convenientlyeffected.

Assuming a 10 ton ladle with 52 inches of metal and a 2 inch diameternozzle, the initial volume flow should be about 157 pounds per secondand should reduce to about 86 pounds per second in the bottom 12 inchesof the ladle. The wire feed rate is matched with the volume flow ofmetal by feeding the weight plus other factors to a computer input,which constantly adjusts the feed rate. Alternatively, the wire feedersare programmable to the extent that with a known ingot size, the wirefeeder can be indexed after each ingot.

As used herein, the term treating agent should be broadly construed andwill include any alloying or treating agent having an effect on thecomposition or form of the final casting. By way of furtherillustration, the following applications may be advantageously carriedout while utilizing the invention:

1. Different alloys such as chromium, molybdenum, vanadium and titaniummay be added to selected castings so that the heat can be split severalways.

2. Controlled rimming action may be effected in the ingot molds bymeasuring the oxygen content in each ingot poured and feeding more orless aluminum wire to tailor the oxygen content.

3. Adding an alloy that is known to fade while holding in a ladle; forexample, boron steel may be made'by deoxidizing the steel during the tapand/or vacuum degassing and then adding the nitrogen fixing agents(titanium and zirconium) and the boron through the wire feeder at thenozzle.

4. Use in a continuous casting operation where'aluminum deoxidized steelcauses nozzle plugging, add aluminum and/or grain refiners in thecontinous cast mold while allowing only semi-killed steel to contact thetundish nozzle, thereby avoiding the aluminumoxide dross problemassociated with adding aluminumv wire.

5. In gray iron applications, alloy and inoculating agents may be addedat the mold so that one base iron may be used to make castings ofdifferent specifications.

is provided. It is also seen that the invention .is particularlyapplicable to the addition of deoxidizing agents for providing fullykilled steel. 1

What is claimed is: 1. A method of adding a treating agent to a moltenmetal stream provided from a nozzle carried in a bottom of a moltenmetal filled ladle or the like and delivered directly from said nozzleinto a mold, comprising: feeding said treating agent in a wire-like formthrough a central passage of a tubular metal member within a stopper rodwhich passes through said molten metal and provides access to saidmolten stream substantially within the said nozzle; and

concurrently with said feeding, passing a coolant fluid through theinterior of said stopper rod in contact with the exterior of saidtubular metal member while preventing said fluid from contacting saidtreating agent.

2. A method as in claim 1 wherein said passing comprises:

introducing a cool incoming stream of said coolant fluid at the top ofsaid stopper rod against the exterior of said tubular metal member;

flowing said incoming stream downwardly against the exterior of saidtubular metal member from the top of said stopper rod to adjacent thebottom thereof, thereby cooling said tubular metal member and thetreating agent passing therethrough while concurrently heating saidincoming stream of coolant fluid; and thereafter directly the heatedstream adjacent the bottom of said stopper rod radially away from saidtubular metal member and about a tubular baffle surrounding said tubularmetal member and therefrom upwardly to the top of said stopper rod andout an outlet provided thereat.

3. A method as in claim 2, including providing a sheath about saidtreating agent to provide added rigidity thereto and protection againstpremature melting thereof.

4. A method of adding treating agents to a molten metal stream asdefined in claim 1, in which the treating agent is added to the centralportion of the metal stream within the nozzle.

5. A method of adding treating agents to a molten metal stream asdefined in claim 4, in which the velocity of molten metal moving throughthe nozzle and past the treating agent is relatively high, whereby thetreating agent is almost immediately dissolved in the metal stream andswept on through the nozzle.

6. A method of adding treating agents to a molten metal stream asdefined in claim 5, in which the treating agents contain deoxidantsselectedfrom the class consisting of aluminum, titanium and zirconium.

7. An apparatus for adding treating agents to molten metal as it flowsfrom a molten metal containing supply reservoir orladle into a mold,comprising:

a nozzle formed in the bottom of said ladle adapted to deliver moltenmetal to a mold,

a valve seat formed at the inlet end of said nozzle,

a stopper rod formed to pass through said molten metal containing ladleand to move into and out of fitting relation with said valve seat forcontrolling the flow of metal through said nozzle,

means for supplying a wire-like treating agent through said stopper rodand into the nozzle; said stopper rod being formed with a hollowinterior in surrounding relation to a tubular metal member with thewire-like treating agent being supplied through a central passage insaid tubular metal member, and

means for circulating coolant fluid through said hollow interior andinto contact with the exterior of said tubular metal member.

8. An apparatus for adding treating agents to molten metals as definedin claim 7, in which the exterior portion of the stopper rod is composedof a ceramic material, and baffle means are provided within the hollowinterior for directing cooling fluid downwardly within the stopper rodfirst against the exterior of said tubular metal member containing thetreating agent, and thence outwardly radially from said tubular. metalmember, around said baffle and upwardly adjacent the ceramic exteriorportion to an outlet.

9. An apparatus as in claim 8, wherein said valve seat is conicallyshaped and an end of said stopper rod which is formed to move into andout of fitting relation with said valve seat is rounded whereby said endcontacts said valve seat over only a part of the area thereof.

10. An apparatus for adding treating agents to molten .metal as definedin claim 9, in which controlled drive means are provided for driving thewire-like treating agent at a controlled rate through the stopper rodand into the metal.

1 1. An apparatus for adding treating agents to molten metal as definedin claim 10', in which means are provided for positioning the stopperrod in open and closed position with respect to the valve seat.

12. An apparatus as in claim 11, wherein said stopper rod isdisassembleable into said tubular metal member,

said baffle and said exterior ceramic material portion.

1. A method of adding a treating agent to a molten metal stream providedfrom a nozzle carried in a bottom of a molten metal filled ladle or thelike and delivered directly from said nozzle into a mold, comprising:feeding said treating agent in a wire-like form through a centralpassage of a tubular metal member within a stopper rod which passesthrough said molten metal and provides access to said molten streamsubstantially within the said nozzle; and concurrently with saidfeeding, passing a coolant fluid through the interior of said stopperrod in contact with the exterior of said tubular metal member whilepreventing said fluid from contacting said treating agent.
 2. A methodas in claim 1 wherein said passing comprises: introducing a coolincoming stream of said coolant fluid at the top of said stopper rodagainst the exterior of said tubular metal member; flowing said incomingstream downwardly against the exterior of said tubular metal member fromthe top of said stopper rod to adjacent the bottom thereof, therebycooling said tubular metal member and the treating agent passingtherethrough while concurrently heating said incoming stream of coolantfluid; and thereafter directly the heated stream adjacent the bottom ofsaid stopper rod radially away from said tubular metal member and abouta tubular baffle surrounding said tubular metal member and therefromupwardly to the top of said stopper rod and out an outlet providedthereat.
 3. A method as in claim 2, including providing a sheath aboutsaid treating agent to provide added rigidity thereto and protectionagainst premature melting thereof.
 4. A method of adding treating agentsto a molten metal stream as defined in claim 1, in which the treatingagent is added to the central portion of the metal stream within Thenozzle.
 5. A method of adding treating agents to a molten metal streamas defined in claim 4, in which the velocity of molten metal movingthrough the nozzle and past the treating agent is relatively high,whereby the treating agent is almost immediately dissolved in the metalstream and swept on through the nozzle.
 6. A method of adding treatingagents to a molten metal stream as defined in claim 5, in which thetreating agents contain deoxidants selected from the class consisting ofaluminum, titanium and zirconium.
 7. An apparatus for adding treatingagents to molten metal as it flows from a molten metal containing supplyreservoir or ladle into a mold, comprising: a nozzle formed in thebottom of said ladle adapted to deliver molten metal to a mold, a valveseat formed at the inlet end of said nozzle, a stopper rod formed topass through said molten metal containing ladle and to move into and outof fitting relation with said valve seat for controlling the flow ofmetal through said nozzle, means for supplying a wire-like treatingagent through said stopper rod and into the nozzle; said stopper rodbeing formed with a hollow interior in surrounding relation to a tubularmetal member with the wire-like treating agent being supplied through acentral passage in said tubular metal member, and means for circulatingcoolant fluid through said hollow interior and into contact with theexterior of said tubular metal member.
 8. An apparatus for addingtreating agents to molten metals as defined in claim 7, in which theexterior portion of the stopper rod is composed of a ceramic material,and baffle means are provided within the hollow interior for directingcooling fluid downwardly within the stopper rod first against theexterior of said tubular metal member containing the treating agent, andthence outwardly radially from said tubular metal member, around saidbaffle and upwardly adjacent the ceramic exterior portion to an outlet.9. An apparatus as in claim 8, wherein said valve seat is conicallyshaped and an end of said stopper rod which is formed to move into andout of fitting relation with said valve seat is rounded whereby said endcontacts said valve seat over only a part of the area thereof.
 10. Anapparatus for adding treating agents to molten metal as defined in claim9, in which controlled drive means are provided for driving thewire-like treating agent at a controlled rate through the stopper rodand into the metal.
 11. An apparatus for adding treating agents tomolten metal as defined in claim 10, in which means are provided forpositioning the stopper rod in open and closed position with respect tothe valve seat.
 12. An apparatus as in claim 11, wherein said stopperrod is disassembleable into said tubular metal member, said baffle andsaid exterior ceramic material portion.